When coating a surface of a plate-shaped substrate, such as a glass substrate, with a coating liquid, use is made of a substrate coating device configured to scan a slit nozzle relative to the surface of the substrate in a predetermined scanning direction perpendicular to the slit with a spacing kept between the nozzle and the surface of the substrate.
In order to coat the surface of the substrate with a desired thickness of the coating liquid uniformly, the coating liquid needs to form a proper bead shape between the tip of the nozzle and the surface of the substrate.
Among conventional substrate coating devices, there is one which is configured to measure the pressure of a pump supplying the coating liquid to the nozzle and the mechanical vibration exerted on the substrate, estimate the bead shape of the coating liquid based on the results of the measurement, and control the discharge pressure of the pump and the spacing between the tip of the nozzle and the surface of the substrate so as to make the bead shape proper (see Patent Document 1).